fix conv history

app.py

@@ -23,7 +23,7 @@ def generate_prompt(instruction, input=None, history=None):
     if (history is not None) and len(history) > 1:
         input = "\""
         for pair in history:
-            if pair[0] is not None and pair[1] is not None:
+            if pair[0] is not None and pair[1] is not None and len(pair[1]) > 0:
                 input += f"User: {pair[0]}\nAssistant: {pair[1]}\n"
         input = input[:-1] + "\"\n" + f"User: {instruction}"
         instruction = "Based on the Conversation History, generate a Response for the User."